Static GNSS positioning

Abstract

A static GNSS receiver, a base station module, a method of estimating a position of a static GNSS receiver, and an associated computer program are provided. An example method includes calculating a first difference between a first pseudorange and a second pseudorange, each made at a first time. A second difference between a third pseudorange and a fourth pseudorange, each made at a second time, is calculated, with the second time different to the first time. A position of the GNSS receiver is calculated based at least in part on the accumulated pseudorange differences.

The invention claimed is: 
     
         1 . A method of estimating a position of a static GNSS receiver, the method comprising:
 obtaining a plurality of GNSS measurements, the plurality of GNSS measurements comprising first GNSS measurements and second GNSS measurements,
 wherein the first GNSS measurements are made by the static GNSS receiver at a first time and comprise a first pseudorange associated with a first GNSS satellite and a second pseudorange associated with a second GNSS satellite, wherein the first GNSS satellite and the second GNSS satellite are different satellites, wherein the first GNSS satellite and the second GNSS satellite are observed by the static GNSS receiver at the first time, 
 wherein the second GNSS measurements are made by the static GNSS receiver at a second time and comprise a third pseudorange associated with a third GNSS satellite and a fourth pseudorange associated with a fourth GNSS satellite, wherein the third GNSS satellite and the fourth GNSS satellite are different satellites, wherein the third GNSS satellite and the fourth GNSS satellite are observed by the static GNSS receiver at the second time, and 
 wherein the second time is different from the first time; 
   calculating a plurality of differences comprising a first difference and a second difference,
 wherein the first difference is calculated between the first pseudorange and the second pseudorange, and 
 wherein the second difference is calculated between the third pseudorange and the fourth pseudorange; and 
   estimating the position of the static GNSS receiver based at least in part on the plurality of differences.   
     
     
         2 . The method of  claim 1 , wherein:
 the plurality of GNSS measurements comprises third GNSS measurements, wherein the third GNSS measurements are made by the static GNSS receiver at a third time and comprise a fifth pseudorange associated with a fifth GNSS satellite and a sixth pseudorange associated with a sixth GNSS satellite, wherein the fifth GNSS satellite and the sixth GNSS satellite are different satellites, wherein the fifth GNSS satellite and the sixth GNSS satellite are observed by the static GNSS receiver at the third time;   the third time is different to the second time and the first time; and   the plurality of differences comprises a third difference calculated between the fifth pseudorange and the sixth pseudorange.   
     
     
         3 . The method of  claim 1 , further comprising maintaining a count of the number of differences in the plurality of differences, wherein the position is estimated in response to the count exceeding a threshold number of differences. 
     
     
         4 . The method of  claim 1 , further comprising:
 calculating a dilution of precision associated with the plurality of GNSS measurements;   comparing the calculated dilution of precision with a dilution of precision threshold; and   responsive to the calculated dilution of precision being below the dilution of precision threshold, estimating the position.   
     
     
         5 . The method of  claim 1 , wherein the first time corresponds to a first epoch at the static GNSS receiver and the second time corresponds to a second epoch at the static GNSS receiver, wherein no GNSS measurement difference is calculated for a fourth time, corresponding to a fourth epoch at the static GNSS receiver, wherein the fourth time is between the first time and the second time. 
     
     
         6 . The method of  claim 5 , wherein zero GNSS satellites are observed, or one GNSS satellite is observed, by the static GNSS receiver at the fourth time. 
     
     
         7 . The method of  claim 1 , wherein one or both of the first GNSS satellite and the second GNSS satellite are the same satellite(s) as one or both of the third GNSS satellite and the fourth GNSS satellite. 
     
     
         8 . The method of  claim 1 , wherein the first GNSS measurements comprise a seventh pseudorange associated with a seventh GNSS satellite observed by the static GNSS receiver at the first time, wherein the plurality of differences comprises the first difference, and a first additional difference calculated between the first pseudorange and the seventh pseudorange. 
     
     
         9 . The method of  claim 1 , wherein the static GNSS receiver is a static GNSS timing receiver. 
     
     
         10 . The method of  claim 1 , further comprising:
 obtaining at least one first further GNSS measurement made by the static GNSS receiver at a fifth time after the position has been calculated; and   calculating a local time at the static GNSS receiver using the estimated position and the at least one first further GNSS measurement.   
     
     
         11 . The method of  claim 1 , wherein the position is calculated by a navigation filter. 
     
     
         12 . A static GNSS receiver, comprising:
 a signal processing unit, configured to track GNSS signals and produce GNSS measurements from the GNSS signals; and   at least one processor, configured to:
 obtain from the signal processing unit a plurality of GNSS measurements, the plurality of GNSS measurements comprising first GNSS measurements and second GNSS measurements,
 wherein the first GNSS measurements are made by the signal processing unit at a first time and comprise a first pseudorange associated with a first GNSS satellite and a second pseudorange associated with a second GNSS satellite, wherein the first satellite and the second satellite are different satellites, wherein the first GNSS satellite and the second GNSS satellite are observed by the static GNSS receiver at the first time, 
 wherein the second GNSS measurements are made by the signal processing unit at a second time and comprise a third pseudorange associated with a third GNSS satellite and a fourth pseudorange associated with a fourth GNSS satellite, wherein the third satellite and the fourth satellite are different satellites, wherein the third GNSS satellite and the fourth GNSS satellite are observed by the static GNSS receiver at the second time, 
 wherein the second time is different from the first time; 
 
 calculate a plurality of differences comprising a first difference and a second difference,
 wherein the first difference is calculated between the first pseudorange and the second pseudorange, and 
 wherein the second difference is calculated between the third pseudorange and the fourth pseudorange; and 
 
 estimate a position of the static GNSS receiver based at least in part on the plurality of differences. 
   
     
     
         13 . A base station for a communications network, comprising the static GNSS receiver of  claim 12 . 
     
     
         14 . The base station of  claim 13 , wherein the base station is an indoor base station. 
     
     
         15 . One or more tangible, non-transitory, computer-readable media storing instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising:
 obtaining a plurality of GNSS measurements, the plurality of GNSS measurements comprising first GNSS measurements and second GNSS measurements,
 wherein the first GNSS measurements are made by a static GNSS receiver at a first time and comprise a first pseudorange associated with a first GNSS satellite and a second pseudorange associated with a second GNSS satellite, wherein the first GNSS satellite and the second GNSS satellite are different satellites, wherein the first GNSS satellite and the second GNSS satellite are observed by the static GNSS receiver at the first time, 
 wherein the second GNSS measurements are made by the static GNSS receiver at a second time and comprise a third pseudorange associated with a third GNSS satellite and a fourth pseudorange associated with a fourth GNSS satellite, wherein the third GNSS satellite and the fourth GNSS satellite are different satellites, wherein the third GNSS satellite and the fourth GNSS satellite are observed by the static GNSS receiver at the second time, and 
 wherein the second time is different from the first time; 
   calculating a plurality of differences comprising a first difference and a second difference,
 wherein the first difference is calculated between the first pseudorange and the second pseudorange, and 
 wherein the second difference is calculated between the third pseudorange and the fourth pseudorange; and 
   estimating a position of the static GNSS receiver based at least in part on the plurality of differences.